Murray workmanlike in sweltering US Open conditions

Andy Murray survived a stuttering start to produce a workmanlike straight sets victory over Germany's Florian Mayer at the US Open.

The defending champion progressed to the fourth round 7-6, 6-2, 6-2 and will now face either Uzbekistan's Denis Istomin or Italy's Andreas Seppi in the last 16.

Murray took nearly an hour to wrap up the opening set on a tie-break, which he won with ease, but closed out the next two sets nearly as quick in a sweltering Arthur Ashe Stadium.

The third seed boomed down seven aces, won 90% of his first serves and kept his cool as Mayer failed to convert only two break point chances.

"It was very tough conditions and he's a very tricky opponent and makes it's hard to get into a rhythm, so I'm glad to get through in three sets," said Murray, who is seeking his third Grand Slam title following his win in Wimbledon this summer.

"I need to start matches quicker, be quicker out of the blocks.

"I think outside expectations of me are higher but there is not as much pressure on me to win coming into these events as there used to be."

Meanwhile, Jamie Murray and Australian partner John Peers showed their battling instincts to progress to the fourth round of the men's doubles.

They lost the first set of their encounter with Brian Baker and Rajeev Ram but rebounded to win the next two on tie-breaks to progress 5-7, 7-6, 7-6.